A new study has shown children with hearing loss can benefit immensely if they receive a cochlear implant before 18 months of age.
The research, led by Johns Hopkins scientists, has appeared in the April 21 issue of the Journal of the American Medical Association (JAMA).
The surgery involves placing a small electronic device into the ear that bypasses the inner ear's damaged nerve cells and transmits sound signals to the brain.
The scientists followed 188 children, ages 6 months to 5 years, with profound hearing loss for three years after receiving cochlear implants at six U.S. hospitals.
They tracked the children's newly emerging ability to recognize speech after the implant, and compared their levels of language development to those of 97 same-age children with normal hearing.
While speech and language skills improved in all children regardless of age after they received a cochlear implant, age emerged as a powerful predictor in just how much improvement was seen.
Lead investigator John Niparko, director of Otolaryngology - Head and Neck Surgery at Johns Hopkins, said: "We identified a clear pattern where implantation before 18 months of age conferred a much greater benefit than later implantation, allowing children to catch up fast, sometimes to nearly normal levels.
"Delaying intervention until a child loses every last bit of hearing deprives the brain of much-needed sound and speech stimulation that is needed to develop language."
Each year of delay, the investigators say, can put a child a year behind in language development.
Therefore all young infants with suspected hearing loss, and those with family history, should be monitored vigilantly and referred for treatment immediately.
While the children in the study never reached the language levels of their hearing counterparts, those who received cochlear implants developed a decidedly better ability to understand and speak than they would have without the device, the researchers found.
When researchers looked at children of all ages, their ability to understand speech grew twice as fast as it would have been expected to without the device.
Their ability to communicate back, either with words or other age-appropriate modes of expression, grew nearly one and a half times faster than it would have without an implant.
Children who received a cochlear implant before age 18 months nearly caught up with their normal-hearing counterparts over the subsequent three years.
Children who received implants after age 3 had language gaps that corresponded directly to the length of delay before receiving the implant.
The study also showed that children implanted before age 18 months managed to reach speech and language developmental milestones much faster than those who received their implants later, revealing gaps between a child's chronological and language ages.
Niparko said: "The impact of early cochlear implantation was greatly augmented in children whose caregivers use language to engage them.
"And we cannot overestimate the importance of caregiver communication with babies at a very early age, whether they have some degree of hearing loss or normal hearing."